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The Planck Early Release Compact Source Catalog: The first all-sky submm survey. Bill Reach. 2009 May 14 Greater IPAC Technology Symposium. IPAC/Planck Team. Planck Mission.
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The Planck Early Release Compact Source Catalog:The first all-sky submm survey Bill Reach 2009 May 14 Greater IPAC Technology Symposium
Planck Mission Planck, the third space mission to measure the anisotropy of the cosmic microwave background (CMB), will launch with the Herschel Space Observatory on April 16, 2009 on an Ariane 5 rocket. With an unprecedented combination of sensitivity, angular resolution, and frequency coverage, Planck is designed to extract essentially all information available in the temperature anisotropies, and to measure the polarization to high accuracy. Planck will image CMB anisotropies with high SNR with two state-of-the-art cryogenic instruments, the Low Frequency Instrument (LFI, 30-70 GHz) and the High Frequency Instrument (HFI, 100-857 GHz). By giving a clear view of the Universe at z1000, these measurements will provide • unprecedented tests of inflation and the physics of the ultra-early Universe • determination of cosmological parameters to extraordi-narily high precision • new understanding of dark energy • the ionization history of the Universe • an unbiased catalog of thousands of galaxy clusters • the large-scale distribution of matter in the Universe, through gravitational lensing Planck will orbit at the Earth-Sun L2 point, spinning at 1 rpm with its spin axis pointed near the Sun. The entire sky is scanned every six months.
Purpose of Planck • Measure the structure of the Cosmic Microwave Background (CMB) • Measure polarization of the CMB
Opening a new Regime Distance • Discovery potential • New phase space (λ, Δν,p) • Wider, sharper, deeper 6 GOODS 5 4 Groth Strip (GTO) 3 SWIRE 2 1 Survey Area
ERCSC Motivation • ERCSC = Early Release Compact Source Catalog • First public data product from the Planck mission • “In exchange for the increased U.S. contribution to the mission, we feel that NASA should obtain guarantees of a timely and public release” (1999, NASA IR and Submm Work. Grp.) • Access to compact source positions and fluxes while Herschel still operates • Herschel key projects based on generic targets to be found by Planck • Cold core project accepted [PI: Juvela] • Second Herschel AO will be released about 20 months after launch, with proposals due approximately 24 months after launch • Likely 3rd (possibly 4th) Herschel AO released ~3 (~4) years after launch • ERCSC will be delivered by the USPDC to DPCs 6 months after completing first sky coverage • L + 6(cruise,PV) + 7(1st sky survey) + 6(work at IPAC) = 19 months after launch
ERCSC Specifications • Requirements • Source lists, one for each frequency (9 altogether) • Deliver ERCSC to DPCs 6 months after first sky coverage is completed • The DPCs will release the catalogs 3 months after receipt • Goals • 90% reliability of compact source identifications • >95% reliability at high galactic latitude • Minimum Expected Performance • Flux density cutoff: SNR 10 or better • Flux density accuracy: better than 30% • Positional accuracy: better than beam(FWHM)/5 (1 sigma radial)
Source Detection • Matched filter • Optimal, if power spectrum of noise, beam, & background are known • Works when CMB-dominated • Can derive from data (patches) • Mexican Hat Wavelet • Approximates matched filter • Sextractor • MHW filter, background grid • Powell Snakes (Bayesian) • Includes matched filter • Uses priors (expected source counts, beam)
Quality Assessment: vs Truth • Comparison of output to input (“truth”) catalog • Useful to select and tune detection algorithms • Cannot be used on the real data
Quality Assessment: Monte Carlo • Inject sources into maps with range of flux and location • Can be used on real data; “bottom line” • Performance determined by Monte Carlo is significantly worse than comparison to truth catalogs.
Conclusions • IPAC is ready to produce the ERCSC (Early Release Compact Source Catalog) for Planck • It will be the first public data product from the Planck mission • IPAC was selected for this task because of its • heritage in delivering quality catalogs • reputation with the stakeholders in Europe • status as the data processing center for JPL-led (from NASA’s viewpoint) astrophysics missions. • Our ERCSC pipeline has the unique capability to assess performance and accuracy using Monte Carlo techniques